Fluid storage vessel



Nov. 27, 1951 1.. P. ZlCK FLUID STORAGE VESSEL 3 Sheets-Sheet 1 Filed May 2, 1947 Nov. 27, 1951 1 P. ZICK 2,576,167

FLUID STORAGE VESSEL Filed May 2, 1947 3 Sheets-Sheet 2 Nov. 27, 1951 L. P. ZICK FLUID STORAGE VESSEL Filed May 2, 1947 flnlllllllllU lea/7470 20%,

Patented Nov. 27, 1951 FLUID s'ronAcnvnssn'r;

Leonard P. Zick, Chicago, Ill';, assignorto Chicago Bridge & Iron Company,. a- -corporation. of Illinois Application May 2', 1941-, swam. 745,558

This invention relates to storage tanks, and more particularly to a storage tank specifically designed to withstand internal pressure.

Liquid storage vessels having a fiat bottom, cylindrical sides and a cone or domed roof are the simplest and least expensive to fabricate of all varieties of tanks. As heretofore manufactured, however, such tanks were not adaptable for use where internalgas pressures are developed within the tank. Considerable work has been done in the development of storage tanks to adapt them to Withstand high internal pressures, but all such tanks have the common fault of complexity oistructure'.

I have invented and am herein disclosing and claiming a storage tank which may take the form of a simple, cylindrical, flat'bottom and domed or coned roof tank which is capable of withstanding internal pressures;

Broadly, I achieve this result by providing stress carrying members having a shape similar to a catenary and being connected to the sides and bottom or top of the vessel by a plurality of vertical tie members.

The invention will be described as embodied in the accompanying drawings in which:

Fig. 1 is a horizontal section, partially broken away for clarity of illustration, through a portion of a liquidstorage tank embodying the invention;

Fig. 2 is a vertical section along line. 2-2 of Figs. 3 to 6, inclusive, are vertical sections through liquid storage tanks of various shapes showing different applications'of: the invention;

Fig. '7 is a horizontal section, partially broken away for clarity of: illustration, through a liquid storage tank embodying a modified form of the invention; and,

Fig. 8 is a vertical section along line 8--8 of Fig. 7.

Referring now to Figs. 3 and 4', In indicate a liquid storage tankhavingraflat bottom H, cylindrical side walls I2 and a domed roof. 13 or cone roof l4; Secured to the inner portion of the side walls is a ring compression member in the form of an angular girder I5 welded to thewalls, which member extends about the interior of the tank on a horizontal plane. Welded to the member I5 is a stress member l6 having its opposite end secured to thebottom H of the tank;

In the embodiment shown, the: stress member I 6 comprises a steel girder having generally the shape of a catenary. Other forms of stress members may be provided, for example, a steel plate: having two edges adapted to be Welded to 12 Claims. (ClaZZU-TU the side walls and bottom, respectively, of the tank and having a. third edge generally in the shape of a catenary; For the purposes of this disclosure and the annexed claims, all such stress carrying members will be hereinafter referred to as c'at'enari'es' or as: tension members substantially'in' the shape of a catenary.

Secured to the bottom of the tank area plura li'ty' of circumferential stiffeners l8, which in the embodiment shown in Fig. 1, comprise angle irons formed into a circle and welded to the bottom of the tank. If desired, the circumferential stifieners |=8 m'ay"be in' the: form of segments of a circle rather than complete circles; as shown. A plurality of vertical tie members 20 have one end welded to the sti'fleners and the other end welded to the catenary.

In the embodiment'shown in Fig. 3, the cate nary is employed onlyto strengthen the sidewalls and the bottom, while in Fig. 4, a second catenary 2| is attached to the side walls and the roof to strengthen the latter member also.

In the embodiment" shown in Fig. 5; the side walls of the tank have a lower portion I-Za in cylindrical form and an upper portion 22 in the form of a cusp circle. Vertical supporting col umns 23 are connected to the bottom of the: tank and tothe roof at'thejuncture ofthe'cusp circle to the roof. The catenary'shown in that figure comprises aflrst portion' 24- having the outer end attached to a ring compression member I50, and the-inner end attached to" the supporting'post 23-; and a second catenary 25 having one end attached to the supporting post and the other end attached to the inner circular segment 20a;

In the embodiment-shown in Fig. 6,,astorage tank has catenariesfla' and 25abetween the side walls and bottom similar to-that just-described in Fig. 5 and is provided with additional catenaries 26 and 21 extending between the upper portion of the side walls I21) and a flat portion 28 of the roof.

The embodiments shown in- Figs. 7 and 8 are similar in most respects to that shown in Figs. 1' and 2 with the exception that circumferential stifleners It are replaced with: radial stifieners 30' which are attached to the bottom Hit of the tank directly beneath the catenaries 3|. Vertical tie members extend between the catenary and the radial s'tiiieners as in the previous embodiments'.

In describing the: manner in which my invention permits the use of the simple tank as a' vessel which can be subjected to internal pressure, it will be understood that the pressure ona flat bottom cannot be eifective in resisting upward in contact with the foundation. Upward pressure on the roof is transferred to the shell and is transferred to the bottom by the shell and by the catenary. The ring compression member resists horizontal forces tending to bulge the tank inward (although this member may be omitted if enough of the shell is made to act so that the internal pressure on the shell balances the horizontal component of the forces exerted by the catenary). The force on the shell is transferred to the catenary in tension which transfers the force in tension to the stiffeners by means of the verticaltie members and to the bottom plates at the inner end of the catenary. The stiffeners, whether they be the circular or radial type, transfer the load to the bottom of the tank and resist tendencies of the bottom to bend. In the preferred construction, the horizontal component of the forces at the supporting posts balance each other so' that the posts exhibit no tendency to bend with-internal pressure. Furthermore, each catenary is so proportioned that the horizontal component at every load point is the same.

. With this type of construction, foundations for the tank would not require excavation, special tamping or special materials as do most pressure vessels resting directly on the ground. Also as there is no dead space below the bottom capacity line, the tank may be drained through the nozzle connection of the shell.

'The invention is applicable not only to conventional flat bottom storage tanks of the vertical cylinder type, but also to other types of structures of parts thereof, for example, it can be applied to the roof, bottom, ends and sides of a vessel having the shape of a rectangular parallelepiped. While I have shown and described my invention in its preferred embodiment, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arfan'gement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.

"-I claim:

1. In a fluid storage tank having a bottom,

atop and side walls between the top and bottom, means stressing the tank against internal pressure comprising a tension member substantiallyv in the shape of a catenary attached to the bottom and attached to the side wall at a point above the bottom, and a plurality of vertical tie members having one end attached to the tension member and having the other end connected to the bottom.

' 2. In a fluid storage tank having a bottom, a top and side walls between the top and bottom, means stressing the tank against internal pressure comprising a tension member substantially in the shape of a catenary having one end attached to the bottom and having the other end attached to the side wall above the bottom, a plurality of stiffeners attached to the bottom and a plurality of vertical tie members having one end attached to the'tension member and having the other end attached to the stiffeners.

3. In a fluid storage tank having a bottom, a top and side walls between the'top and bottom, means stressing the tank against internal pressure comprising a ring compression member attached to the side walls above the bottom, a tension member substantially in the shape of a catenary attached to the bottom and to the ring compression member, and a plurality of vertical tie members having one end attached to the tension member and having the other end connected to the bottom.

4. In a fluid storage tank having a flat bottom, a top and side walls, said side walls having at lease a portion substantially cylindrical in shape, means for stressing the tank against internal pressure comprising a ring compression member attached to the cylindrical portion of the side walls above the bottom of the tank, a tension member substantially in the shape of a catenary attached to the bottom and to the ring compression member, a plurality of stiffeners attached to the bottom and a plurality of vertical tie mem bers having one end attached to the tension member and having the other end attached to the stiffeners. V

5. Apparatus of the character described in claim 4 in which said ring compression member is adapted to resist horizontal forces exerted by the tension member in response to internal pressure.

6. Apparatus of the character described in claim 4 in which said bottom stiffeners are in the formof concentric circles.

'7. Apparatus of the character described in claim 4 in which said bottom stiffeners are in the form of circular segments.

8. Apparatus of the character described in claim 4 in which said bottom stiffeners are in the form of radial segments.

, 9. In a fluidstorage tank having a substantially flat bottom and substantially vertical side walls, means stressing the vessel against internal pressure comprising a tension member substantially in the shape of a catenary having one end attached to the bottom of the tank and having the other end attached to the side walls at a point above the bottom, and a vertical tie member attached to the tension member intermediate its ends and attached to the bottom of the tank.

' 10. Apparatus of the character described in claim 9 in which said vertical tie member is connected at its lower end to a stiffener attached to the bottom'of the tank.

11. In a fluid storage tank having a first portion lying in one plane and a second portion lying in another plane, means stressing said portions agaist distortion from internal pressure comprising a tension member substantially in the shape of a catenary having one end attached to said first portion and having the other end attached to said second portion, a plurality of tie members attached to said tension member and to one of said portions, said tie members lying in a plane substantially perpendicular to the last mentioned portion.

' 12. In a fluid storage tank having a fiat bottom, vertical side walls, a top, and supporting posts between the top and bottom, means stressing the vessel against internal pressure comprising a first tension member substantially in the shape of a catenary havingone end attached to the post above the bottom and having the other end attached to the side walls above the bottom, a second tension member substantially in the shape of a catenary attached to the post above the bottom and to the bottom, and a plurality of vertical tie members attached to the tension members and to the bottom of the tank.

LEONARD P. ZICK. 5

REFERENCES CITED The following references are of record in the file of thls patent: m

, 6 UNITED STATES PATENTS Number 

